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New Construction Radon Systems in Sioux City, IA
Building in Sioux City? Radon-resistant construction is easiest and most economical to put in while the house is open. This page explains what it involves and how to follow up.
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Iowa's New-Home Radon Law
In May 2026, Iowa Governor Kim Reynolds signed House File 2297, which news reports describe as requiring passive radon mitigation in newly constructed single-family and two-family homes. Reports say the law takes effect July 1, 2026, and is enforced by local governments and the state building code commissioner. Because the details of how it applies to a given permit can change, ask your builder and your local building department how the requirement applies to your project.
The idea behind the law is simple: radon is easiest to plan for at the start. Running a pipe through a house under construction is a modest job compared with retrofitting a finished house.
What a Passive Radon System Is
A passive system is the plumbing for a radon fix, without the fan. It typically includes a layer of gas-permeable material such as clean gravel under the slab, plastic sheeting over it, sealed joints and cracks in the slab, and a vent pipe running from under the slab up through the house and out above the roof.
In a passive system, natural forces, including the warm air rising in the house, can draw some soil gas up the pipe. That can reduce radon on its own, but passive systems do not always bring levels down enough. A passive system gives you a head start and a place to add a fan if needed.
The EPA notes that a passive system can be converted to an active one by adding a fan to the vent pipe. That is typically much simpler than building a system from scratch in a finished house.
Core Features of Radon-Resistant Construction
- Gas-permeable layer. A layer of clean gravel under the slab, or another approved material, so soil gas can move toward the pipe.
- Plastic sheeting. A sheet over the gas-permeable layer under the slab, which helps limit soil gas and moisture.
- Sealing and caulking. Sealing cracks, control joints and openings in the slab and foundation walls.
- Vent pipe. A pipe from the gravel layer up through the house to above the roof, away from windows and air intakes.
- Junction box. Wiring or a junction box in the attic near the pipe so a fan can be added later without a major electrical job.
- Sump pit covers. Airtight covers on sump pits, with the pit tied to the system where appropriate.
Test After You Move In
Passive features reduce risk but do not guarantee a low level. Test your new home after you move in, using the guidance on our radon testing page. If the result is 4 pCi/L or higher, a credentialed professional can add a fan to activate the system and retest afterward. Our mitigation page explains how active systems work.
Testing is useful even when a house was built with radon-resistant features, because levels depend on soil, weather, the foundation and how you use the house. The Iowa Department of Public Health says radon is found in new and old homes alike.
Questions to Ask Your Builder
- What radon-resistant features are in the plans, and are they part of the permit?
- Where will the vent pipe run and where will it exit the roof?
- Is there a junction box in the attic so a fan can be added?
- Who will test the house after completion, and when?
- If the post-completion test is high, who handles the fan and the follow-up test?
- Will you provide the documentation of the radon features at closing?
If you want help finding a company to add a fan or test a new home, request a quote and we will route it to an independent local company.
Common Questions
Does Iowa require radon systems in new homes?
News reports on House File 2297, signed in May 2026, describe a requirement for passive radon mitigation in newly constructed single-family and two-family homes, effective July 1, 2026. Check with your builder and local building department for how it applies to your permit.
What is a passive radon system?
A passive system is a vent pipe and gas-permeable layer under the slab that can draw some soil gas outside without a fan. A fan can be added later to make it an active system.
Do I still need to test a new house?
Yes. Passive features reduce risk but do not guarantee a low level. Test after you move in and retest after major changes.
Nearby Communities
We route requests from Sioux City and the surrounding area. Pick your town, or see the full service area list.
Know Your Radon Level, and Fix It If You Need To
Call or send a request. We will route it to an independent, insured local company that handles radon work in the Sioux City area.